It is common in the art to install photovoltaic (PV) arrays at an offset height above a support surface, such as a roof surface (of shingle, tile, roof membrane or the like). Such a mounting arrangement may provide an air gap beneath the PV array. The offset height distance may provide space for wire management and to allow for PV arrays or PV modules to be mounted above vent pipes and other common roof obstructions. Gaps between PV module frames on the top surface of a PV array may be required to allow space for mounting hardware as well as to allow for dimensional tolerance variation, thermal expansion and the like.
The presence of an air gap opening on the sides of a PV array, as well as between PV module frames on the top surface, may result in organic debris (such as leaves and sticks) entering and becoming trapped under the array, which may in turn result in a fire safety hazard. Rodents/birds/insects and other pests may also enter through these opening and contribute to the accumulation of flammable material through the building of nests, as well as potentially damaging electrical wires contained beneath the array. Regardless of debris, flames from a building fire may enter the air gap beneath an array and compromise the fire safety rating of the roofing material located underneath by trapping hot air, gases, vapor or plasma that typically dissipate if not otherwise confined. Furthermore, in some installations a PV array may be installed such that a gap beneath the PV array allows a viewer to see underneath the PV array, thereby degrading the overall aesthetic appearance of the PV array.
It may be therefore desirable to have a method, apparatus and system for preventing animal intrusion and organic debris from accumulating beneath arrays in addition to impeding open flames from entering the air gap and blocking or limiting the spread of flame over the roof. It may also be desirable to have an apparatus, method and system for screening unfavorable view angles beneath a PV array, or otherwise obscuring the area beneath a PV module or portions of a PV array. Some attempts have been made to affix skirt elements to an edge of a PV array for visual screening. However, these systems suffer from a number of drawbacks.
Prior skirt systems do not appear to provide adequate structural support. For example, prior systems typically connect a skirt to a mounting foot or a rail of a PV array yet not to a coupling that may be located in a region where the corners of four PV modules meet. Therefore, on a steep roof the weight of the PV array plus other loads, such as snow or an installation technician may not be properly supported, especially in the 4-corners region.
Prior skirt systems also do not appear to provide a means to accomplish the desired blocking the spread of flames or providing visual aesthetics by blocking a view of the area beneath a PV module or array, while allowing for enough airflow to adequately reduce the temperature of the PV array. It is well known in the art that increased PV module temperature reduces total power output. Therefore, it is desirable to provide some means for allowing airflow beneath a PV array.
Prior skirt systems do not appear to provide skirts that adequately block animals and debris since such systems do not typically cover enough of the gap beneath a PV array to be sufficient. For example, roof surfaces are rarely flat yet prior systems provide only a rigid, flat screen, thereby resulting in gaps between the screen and the roof surface. Prior systems also do not provide height adjustability so that a screen may be moved closer to or in contact with a roof surface.
Prior skirt systems require numerous parts which increase the cost of installation for the PV array.
Prior skirt systems also appear not to provide a simple method, apparatus or system for creating a ground bond between a skirt and a PV array. In most, if not all cases of prior systems a separate ground wire would be required to properly ground the skirt, as is required by building regulations in many regions of the world. The parts and labor associated with running a separate ground wire to a skirt is a significant cost. Furthermore, many on-roof grounding systems have suffered problems in the field due to corrosion, which exacerbates the problems of post-installation addition of grounding wires.
The foregoing examples of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the figures.